Harnessing prefrontal-hippocampal theta synchrony to enhance memory-guided choice.

Working memory is correlated with prefrontal-hippocampal oscillatory synchrony, but whether endogenous patterns of synchronized brain rhythms can be used to bias future choice remains unknown. Here, we developed a brain machine interface that detected states of strong and weak theta synchrony for task and neural manipulation. States of strong prefrontal-hippocampal theta coherence were characterized by strengthened prefrontal theta rhythms and were used to enhance memory-guided choice. In follow up experiments and analyses, we show that strong prefrontal-hippocampal theta coherence was associated with task engagement, phase modulation of prefrontal neurons to ventral midline thalamic theta, and heightened excitability in a select group of neurons. Through optogenetic manipulation of the ventral midline thalamus, we produced prefrontal theta rhythms and enhanced prefrontal-hippocampal oscillatory synchrony. These experiments show that prefrontal-hippocampal oscillatory synchrony can be used to bias memory-guided choices and provide evidence in support of the communication through coherence hypothesis.